The present invention disclosed herein relates to an organic light emitting layer, and more particularly, to a color tunable organic light emitting layer with high light extraction efficiency.
An organic light emitting device, for example, an organic light emitting diode is a light emitting device, where excitons occur when holes supplied from an anode electrode and electrons supplied from a cathode electrode are combined in an organic light emitting layer therebetween and they are recombined again. The organic light emitting diode as a self-light-emitting device is applied to a display device and developed due to its wide viewing angle, fast response sped, and high color reproduction rate. Furthermore, recent research and development on applying an organic light emitting diode are actively in progress.
FIG. 1 is a schematic view illustrating a layer stacked structure of a typical organic light emitting diode. The organic light emitting diode includes a sequentially stacked substrate 10, anode (i.e. a transparent electrode) 20, organic light emitting layer 30, cathode (i.e. a reflective electrode) 40, and protective layer 50.
The organic light emitting diode may be configured to emit R (red), G (green), and B (blue) separately, or to emit white color only. At this point, in order to express a desired color, a plurality of organic light emitting layers emitting a light of different wavelengths may be combined and used.
Korea Patent Application Publication No. 2007-0008071 discloses a technique that increases brightness and makes pixelization easy by stacking the widths of organic light emitting structures uniformly and vertically in order to make an area of a RGB sub pixel identical to that of a pixel. However, by such a structure, the light generated from a sub pixel at the middle is reflected at a sub pixel at the end, and then is emitted toward the external. As a result, light efficiency is deteriorated.